1. Create a HTML5 application
2. Open index.html (if not opened already)
3. Change the browser to Android Device (Chrome)
4. Run the project - this will populate the CSS Styles window and the button to enable inspect mode will appear in the top right corner of this window; so far so good, the button is in your view
5. Open a CSS file (or a JavaScript file) in the editor - the CSS Styles will be changed, and now it no longer displays the button
=> When I want to switch to inspect mode now, I can not do it easily (there is no UI for this in the mobile browser itself, like there is for Chrome). I need to go back to the HTML file to make the button appear (unless I remember the keyboard shortcut), and this is neither convenient nor intuitive/discoverable.
There should be a more easy and discoverable way to switch to select mode even when a different file than a HTML file is at the front.

I'm not sure I'm crystal clear on the issue here. There isn't an inspect mode option in the CSS Styles window, so I'm not sure what it has to do with not having access to inspect mode in the mobile browser? Sorry if I'm being dense (!), but can you clarify?
Also, do we really have no option for offering some kind of UI in chrome when on a mobile device?

Created attachment 133752[details]
Screenshot of the CSS styles window
> There isn't an inspect mode option in the CSS Styles window
See the attached screenshot - it's the button at the top right (the screenshot also shows its tooltip. This is a placeholder, we can decide to put it elsewhere.
> Also, do we really have no option for offering some kind of UI in chrome
> when on a mobile device?
Not sure, this is for Honza S to clarify. I believe he mentioned the possibility to inject some UI directly as a part of the page, but this may be problematic from both functional and visual point of view. Also it may require substantial effort. But Honza can provide a more definitive answer.

> Also, do we really have no option for offering some kind of UI in chrome
> when on a mobile device?
Unfortunately, there is no extension support for mobile Chrome, i.e., there is no way to extend the UI of the browser itself. The only possibility I am aware of is to insert some stuff into the inspected page directly, but this approach has several drawbacks (mentioned by Petr in the previous comment).
I suggest to resolve this issue by move of the Inspect Mode button from the CSS Styles view into the top-right corner of the Browser DOM view (next to URL). The Inspect Mode is mainly about selection which is driven by Browser DOM view by now. Therefore, the Inspect Mode button fits there well.

Both toggle buttons ("Style Element States" and "Inspect mode...") are often not visible on displays with lower resolution because there are shifted by name of inspected element to the right. One has to make CSS Styles wide to make them visible again